Hi
Are you taking a holiday or are you going to be looking for work? I'm an Australian who has travelled a lot around the country so can give you any travel tips.
If you will be looking for work and need visa information and a job, this site called Jobaroo
www.jobaroo.com will be able to help you out! It's got info for backpackers and working travellers going to Oz, as well as job opportunities and agencies to register with. Good luck!